title: Expression of complement components coincides with early patterning and organogenesis in Xenopus laevis.
abstract: The complement system is the central component of innate immunity and an important player in the adaptive immunity of vertebrates. We analyzed the expression patterns of several key members of the complement cascade during Xenopus development. We found extensive expression of these molecules already during gastrula/early neurula stage. Remarkably, several genes also showed an organ-specific expression pattern during early organogenesis. Early expression is notable for two different expression patterns in the neuroectoderm. In one group, there is early strong neural plate and neural precursor expression. This is the case of properdin, C1qA, C3 and C9. The second pattern, seen with C1qR and C6, is noteworthy for its expression at the periphery of the neural plate, in the presumptive neural crest. Two genes stand out for their predominantly mesodermal expression. C3aR, the message for the cognate receptor for C3 in the complement cascade, is expressed at the same time as C3, but in a complementary, reciprocal pattern in the mesoderm. C1qA expression also predominates in somites, pronephros, visceral mesoderm and ventral blood islands. Finally, several genes are characterized by later expression in developing organs. C1qR displays a reticular pattern consistent with expression in the developing vasculature. The late expression of C1qA and C3bC4b is strongest in the pronephros. Finally, the expression of properdin in the hindbrain and in the developing lens are novel findings. The expression patterns of these molecules suggest that these components of the complement system may have in Xenopus a so far undefined developmental role.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine (BCM), Houston, Texas 77030, USA. mclin@bcm.edu
authors.forename: Valérie A
authors.initials: VA
authors.lastname: McLin
authors.forename: Cheng-Hui
authors.initials: CH
authors.lastname: Hu
authors.forename: Rina
authors.initials: R
authors.lastname: Shah
authors.forename: Milan
authors.initials: M
authors.lastname: Jamrich
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000196:embryology / Q000276:immunology; D019521:Body Patterning / Q000235:genetics* / Q000276:immunology*; D015922:Complement C1q / Q000235:genetics; D003176:Complement C3 / Q000235:genetics; D003186:Complement C9 / Q000235:genetics; D003165:Complement System Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D007908:Lens, Crystalline / Q000196:embryology / Q000276:immunology; D008648:Mesoderm / Q000196:embryology / Q000276:immunology; D054259:Neural Tube / Q000196:embryology / Q000276:immunology; D038081:Organogenesis / Q000235:genetics / Q000276:immunology; D011414:Properdin / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics / Q000276:immunology; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000276:immunology*
chemical_list: D003176:Complement C3; D003186:Complement C9; D029867:Xenopus Proteins; D011414:Properdin; D015922:Complement C1q; D003165:Complement System Proteins